1. Field of the Invention
The present invention relates to a solid-state imaging apparatus and a method for manufacturing the same.
2. Description of the Related Art
In recent years, inexpensive digital camera and video camera of high quality are wide-spread due to the progress of a solid-state imaging apparatus. In particular, a CMOS-type solid-state imaging apparatus which has an active element in a pixel and can convert a peripheral circuit to an on-chip type has been remarkably improving its performance, and is partially being substituted for a CCD sensor. The CMOS-type solid-state imaging apparatus has MOS transistors and photodiodes in a pixel region, and the peripheral circuit unit is constituted by the MOS transistors. A low cost which is one of advantages of the CMOS-type solid-state imaging apparatus can be achieved by commonizing a process of manufacturing the MOS transistors in the pixel unit and a process of manufacturing the MOS transistors in the peripheral circuit unit.
In addition, the solid-state imaging apparatus is being multi-pixelated, and thereby the pixel pitch is reduced. Accordingly, it becomes essential to refine the photodiodes, the transistors and the wiring.
Japanese Patent Application Laid-Open No. 2006-073733 discloses a CMOS-type solid-state imaging apparatus having a configuration in which a semiconductor region and a gate electrode are connected through metal wiring. Japanese Patent Application Laid-Open No. 2002-368203 discloses a CCD-type solid-state imaging apparatus that has a configuration in which an output transistor and a floating diffusion are connected through a shared contact so as to enhance a coefficient of electric charge conversion by reducing the capacitance.
In the CMOS-type solid-state imaging apparatus, a light coming from an image passes through a wiring layer and is incident on the solid-state imaging apparatus, but all lights are not vertically incident thereon. Incident angles of the lights which are incident from an optical system vary according to the F value of an optical lens and the position on the solid-state imaging apparatus.
As the pixel pitch becomes more refined, a space between adjacent pixels becomes narrower, which cause a problem of a crosstalk that an incident light leaks into an adjacent pixel.
Furthermore, in a solid-state imaging apparatus which reproduces a color of the image with a color filter having a Bayer array or the like, the light which has leaked to the adjacent pixel is converted to a signal of another color, and accordingly causes a deterioration of image quality, which is referred to as a color mixture. In the above description, the crosstalk can be reduced by setting a sufficient space between the pixels, but then, the pixel becomes difficult to be refined.
An object of the present invention is to provide a solid-state imaging apparatus which can achieve the refinement of the pixel by improving optical properties such as the crosstalk of the light among the pixels and a method for manufacturing the same.
Another object of the present invention is to provide a method of manufacturing a solid-state imaging apparatus, which can reduce the pollution of metal, which can occur when a structure of being capable of refining the pixel is manufactured, by enhancing optical properties such as the crosstalk of the light among the pixels.